The invention relates to a damper adjustment device for pianos, and in particular to the damper timing in grand and upright pianos.
An acoustic piano, by way of a keyboard and hammer mechanism (action), excites tensioned strings to produce tones. The strings are dampened by a second mechanism, the damper assembly. The xe2x80x9cfeelxe2x80x9d of the piano action, that is, the real and perceived heaviness of the piano keys, depends on the damper timingxe2x80x94the point in the piano keystroke at which the damper is removed from the string. If the dampers are displaced from the strings early in the piano keystroke, it takes more force to depress the keys, making the keys xe2x80x9cfeel heavyxe2x80x9d. On the other hand, if the dampers are displaced later in the keystroke, the keys feel xe2x80x9clivelierxe2x80x9d to the pianist. Personal preferences can dictate the exact timing desired.
Referring to FIGS. 1 and 2, a prior art damper assembly 100 of a typical grand piano includes cushions 1 mounted on a damper head 2, which is typically held above a piano string 30 as shown. When cushions 1 are in contact with string 30, cushions 1 dampen vibrations of string 30. Cushions 1 are typically made of felt or another material which can absorb vibration, and damper head 2 is typically made of wood. Damper head 2 is supported by a rigid damper wire 3 attached at one end 3a to damper head 2 and at an opposite end 3b to a top flange 5 by a locking mechanism 4, e.g., a barrel and screw as shown in FIG. 1. Top flange 5 is mounted to an underlever 7 to rotate relative to underlever 7 about a pin 6. Underlever 7 is mounted to a mounting flange 8 to rotate relative to mounting flange 8 about a pin 31. Mounting flange 8 is attached to other structural elements, described below, by a flange screw 9.
FIG. 2 demonstrates how the prior art damper assembly of FIG. 1 operates to displace cushions 1 from piano string 30 when a piano key 10 is depressed. As shown in FIG. 2, a downward force 32 is applied at a proximal end 35 of piano key 10. Since piano key 10 rests on a fulcrum 33, this results in upward displacement of the opposite, distal end 37 of piano key 10 (arrow 39). Distal end 37 comes in contact with an underside 36 of underlever 7, and subsequently rotates underlever 7 about pin 31 (arrow 41), transmitting the upward displacement through top flange 5, damper wire 3 and damper head 2 (arrow 43), lifting cushions 1 off piano string 30. This allows an undamped vibration of piano string 30 when struck by a hammer (not shown). Associated movements of other components of the piano action, causing the hammer to strike piano string 30 and produce a tone, are not shown.
An important adjustment in the regulation of piano actions is the proper spacing 14 between the underside 36 of underlevers 7 and the distal end 37 of keys 10. This determines the distance the distal end of the key must travel before damper head 2 is displaced from string 30, and thus the amount of downward force 32 which must be applied to proximal end 35 of the piano key 10. In practice, the spacing is adjusted by the xe2x80x9cfeelxe2x80x9d of a trained technician. According to the prior art, this adjustment is made by loosening locking mechanism 4 between top flange 5 and damper wire 3, rotating the underlever about pin 31 to provide the desired spacing 14, and then retightening locking mechanism 4. In a typical prior art grand piano, this adjustment must be repeated for the sixty damper assemblies present in the piano. Analogous adjustments are made for upright pianos as well.
Referring to FIG. 3, prior art damper assembly 100 typically includes a rail assembly 41 with a damper tray 11. Damper tray 11, designed to contact the underside 36 of each of a number of underlevers 7 in a group of underlevers, is typically operated by a foot pedal. This allows the vibrations of all piano strings associated with the group of underlevers to remain undamped as long as the foot pedal is operated. Rail assembly 41 includes a pair of stationary blocks 12 to which damper tray 11 is coupled by pivot pins 16 received in pivot cavities 17 defined by blocks 12 for rotation relative to blocks 12 about pins 16. Pivot blocks 12 are fixedly mounted to piano case 40 by mounting screws 19.
When damper tray 11 is rotated, for example, by actuating a mechanism (not shown) attached to a foot pedal (not shown), a pad 34 attached to tray 11 (typically made of felt or other material capable of absorbing noise) contacts the underside 36 of underlever 7, causing upward displacement of cushions 1 through the same mechanism as described above with respect to the piano key action. Rotation of damper tray 11 results in motion of underlever 7, even before contact between pad 34 and the underside 36 of underlever 7. This is true unless the axes of rotation of underlever 7 (through pin 31) and damper tray 11 (through pins 16) are coincident.
FIG. 4 depicts an alternate embodiment of a prior art damper assembly 100a. Damper assembly 100a includes an underlever 7a mounted to piano casing 40 by a rail assembly 41a, and a damper tray 13a independently mounted to the piano casing 40. Rail assembly 41a is mounted to piano casing 40 in a fixed position with screws 43a. Damper tray 13a includes a pad 34a for contacting the underside 36a of underlever 7a. Tray 13a is mounted to piano case 40 with mounting flanges 42a and screws 44a. Tray 13 pivots about pins 46a. Upward force on damper tray 13 causes pad 34 to contact the underside of underlever 7. Further movement of tray 13 causes upward displacement of cushions 1 in an equivalent way as described with respect to FIG. 3, but rotation of independent damper tray 13 does not, in and of itself, cause movement of underlever 7 until pad 34 contacts the underside of underlever 7. That is, the rotation of underlever 7 and damper tray 13 are not coupled until pad 34 contacts the underside 36 of underlever 7.
Referring to FIG. 5, a piano action of an upright piano, according to the prior art, includes a damper assembly 200. As in a grand piano, cushions 101 dampen vibrations of piano strings 130. Cushions 101 are mounted on a damper head 102 (typically made of wood), which is positioned adjacent to string 130 as shown. Damper head 103 is supported by a rigid damper wire, a lower end 105 of which is press-fit into an underlever 136. Underlever 136 is rotatably connected to a flange 137 by a pin 106. Flange 137 is mounted to a primary action rail 138.
In operation, piano key 110, resting on a fulcrum 133, is subjected to a downward force 132 at proximal end 134. This results in upward displacement (arrow 107) of the opposite, distal end 135 of piano key 110. Distal end 135 comes in contact with the underside of one end 141 of a wippen assembly 139, causing the latter to pivot about a pin 131. The opposite end 143 of wippen assembly 139, which has a spoon 140 mounted on its upper surface 145, is thereby rotated downward (arrow 146) and contacts underlever 136, producing rotation of underlever 136 about pin 106. This causes the upper end 149 of underlever 136 (and consequently damper wire 103, damper head 102 and cushion 101) to move away from piano string 130 (arrow 148), acting against the bias introduced by a wire spring 141. This allows piano string 130 to vibrate freely when it is struck by a hammer 151.
The spacing 114 between spoon 140 and underlever 136 is important in determining when, during the piano keystroke, cushion 101 is lifted off string 130. The greater the spacing 114, the later during a keystroke cushion 101 is displaced from string 130. This significantly affects the way the keys feel to a pianist, as described above. As with grand pianos, space 114 is individually adjusted for each damper assembly. For either type of piano, inconsistencies are introduced with such individual adjustments, and the individual adjustments are time-consuming and difficult to perform.
The invention results from the realization that significant advantages can follow from a damper assembly which allows adjustment of the timing of the underlevers (that is, the spacing between underlevers and piano keys) in a groupwise, rather than individual, fashion.
In one aspect, the invention features a damper assembly for a piano. The damper assembly includes a rail assembly with an adjustable mount for mounting the rail assembly to the piano case, and a plurality of underlevers coupled to the rail assembly.
Embodiments of this aspect of the invention may include one or more of the following features.
The underlevers are rotatably coupled to the rail assembly. The rail assembly is configured for vertical adjustment relative to the case, for example, continuous adjustment (in which the rail assembly can define a vertical slot) or discrete adjustment (in which the rail assembly defines discrete openings arranged vertically). The rail assembly has two ends, and the adjustable mount includes a slot in a region of one end and another slot in a region of the opposite end. The adjustable mount includes an adjustment screw in each slot.
In one illustrated embodiment, the rail assembly includes a rail and an attached damper tray. The rail is configured for mounting to the case for rotation relative to the case. The adjustable mount includes mounting blocks, and the rail is mounted to the blocks for rotation relative to the blocks. The mounting blocks each define an adjustment slot. In another illustrated embodiment, the damper assembly includes a damper tray mounted to the case independently of the rail assembly.
The damper assembly includes a plurality of damper wires. Each of the underlevers is coupled, for example, rotatably coupled, to a respective damper wire.
In other embodiments, the piano has a horizontal axis and the rail assembly is configured for horizontal adjustment relative to the case.
According to another aspect of the invention, a piano includes a case and a damper assembly. The damper assembly includes a rail assembly having an adjustable mount which mounts the rail assembly to the case, and a plurality of underlevers coupled to the rail assembly.
Embodiments of this aspect of the invention may include one or more of the following features.
The mount includes adjustable mounting blocks coupled to the rail assembly, and mounting screws for fixing the mounting blocks to the case. The mounting blocks define slots for receiving the mounting screws. The mount includes slots defined in the rail assembly and mounting screws received in the slots for fixing the rail assembly to the case.
According to another aspect of the invention, a method of simultaneously adjusting a plurality of piano underlevers in a piano includes mounting a damper assembly to a piano case with an adjustable mount, the damper assembly including a rail assembly and a plurality of underlevers coupled to the rail assembly, and adjusting the position of the rail assembly relative to the case.
Embodiments of this aspect of the invention may include one or more of the following features.
The method includes rotatably coupling the underlevers to the rail assembly. The piano has a vertical axis, and the step of adjusting the rail assembly position relative to the case includes vertically adjusting the rail assembly position. The step of adjusting the rail assembly position relative to the case includes adjusting a spacing between the underlevers and a corresponding group of piano keys. Alternatively, the step of adjusting the rail assembly position relative to the case includes horizontally adjusting the rail assembly position.
The invention provides a number of advantages over previously known damper adjustment devices and methods. The inventive damper adjustment device permits the adjustment of a group of underlevers, rather than the adjustment of individual underlevers which has previously been required. More specifically, the inventive damper adjustment device permits the adjustment of distances between underlevers and their corresponding elements for displacing damper heads from piano strings without loosening the locking mechanisms of individual damper assemblies. Individual artists prefer the same xe2x80x9cfeelxe2x80x9d for all the keys. Thus, the invention advantageously minimizes the introduction of string-to-string inconsistencies between the damper assemblies. The inventive damper adjustment device allows factory-established settings to be maintained for long periods of time. Further, the time and skill required to regulate damper settings are reduced.
Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.